Crossover Shipgirls: Building a Dimensional Empire from Scratch

”Why isn’t the Commander here yet?”

In the naval base office, Formidable, Essex, Implacable, and several other shipgirls sat idly at their desks, all staring at the empty chair at the center of the room.

It was already an hour past their scheduled start time, and the pile of documents awaiting the Commander’s approval continued to grow.

”Belfast, maybe you should go wake him up?” Formidable suggested, slumping over her desk. The weight of her moral complexities made the desk creak and wobble.

”I already checked. The Commander wasn’t in his room last night,” Belfast replied, shaking her head.

”After working overtime, it seems he didn’t return there.”

”Oh-ho—”

”Could it be that he passed out after eating your Stargazy Pie or one of Tohru’s Eldritch Fusion dishes?” Formidable teased, twirling one of her twin tails.

”Speaking of which, when I returned from training last night, I think I saw the Commander heading to Iris Libre’s dorms with the flagship…” a blonde-haired cruiser with neatly coiled hair chimed in.

”No way! The Commander spent the night in Richelieu’s room? That’s huge news!” Formidable perked up, her interest fully piqued.

”Did you hear anything? Like…”

Implacable leaned in, pressing a finger to her lips and letting out a soft, ambiguous hum.

The room immediately erupted into blushing faces.

Are you really a nun? You look more like a succubus!

”Nothing like that! I wouldn’t dare pry into the flagship’s private affairs, and we don’t even live in the same dorms!”

Jeanne d’Arc was practically ready to flee the room in embarrassment.

Click—

The door swung open just as the shipgirls’ chatter reached a fever pitch.

Setsuna walked in, with Richelieu and Taihou close behind, along with a few other shipgirls and heroic spirits.

”Sorry for being late,” he said, striding to his chair.

Behind him, the two shipgirls subtly squared off. As soon as Setsuna sat down, Taihou and Richelieu each claimed a seat on either side of him.

The tension between them was palpable, their gazes at each other sharp and unyielding. But when they turned to Setsuna, their eyes softened into a syrupy sweetness that could make anyone shiver.

”...What’s going on here?” Formidable mumbled, utterly baffled by the scene.

”Master came out of Richelieu’s bedroom this morning, and Taihou caught him,” Jeanne Alter said bluntly.

The shipgirls in the room immediately conjured mental images of storms brewing.

Both Richelieu and Taihou were formidable forces. Though they would never go too far under Setsuna’s orders, their rivalry was bound to spark some friction.

As the murmurs grew, Richelieu suddenly stood up, glancing around the room. Most of the Vanguard Fleet was gathered in the office.

”I have something to announce,” she said, her voice steady and commanding.

”From this moment on, I will serve as the Commander’s Oath-bound ship and Secretary Ship, continuing to lead Iris Libre and the Starsea Alliance Fleet.”

”In the name of freedom and glory, until the day I am sunk in battle, I swear to protect him and Iris Libre with my life.”

Richelieu’s words were precise and serious, carrying both pride and a faint hint of boastfulness.

To her, this bond deserved to be known by every shipgirl in the port, a public declaration of her connection with the Commander.

”Ohhh—”

The gathered shipgirls were visibly taken aback.

Formidable, Implacable, Belfast, and others couldn’t hide the hint of envy in their eyes.

Initially, many of them hadn’t truly regarded Setsuna as their Commander, merely seeing him as someone they had come to assist.

But as time went on, Setsuna had shown them things they’d never imagined—leading them toward the stars and pursuing goals that no flagship before them had accomplished.

Even strict leaders like Enterprise and Bismarck had come to acknowledge him as a true Commander.

For those shipgirls who interacted with him regularly, admiration had quietly taken root, and Richelieu’s public declaration only deepened those feelings.

”Well… it’s not surprising. She is the Secretary Ship,” Belfast murmured, clenching her fists as she resolved to use her position as Royal Maid to her advantage.

”Do I still have a chance?” Saratoga muttered, glancing down at herself. The difference between her and carriers like Taihou, Formidable, and Implacable felt just a little too noticeable.

”Cheating cat,” Taihou muttered, giving Richelieu a nuclear-grade glare.

The Cardinal of Iris Libre, unfazed, returned an equally sharp look.

”Your possessiveness is far too unhealthy, Taihou,” Richelieu said coolly. ”It can be counterproductive at times.”

”Eh?” Taihou flinched, the words hitting a nerve. She turned her pitiful gaze toward Setsuna.

”Commander, am I really that annoying…?”

”Ahem, no,” Setsuna coughed awkwardly, deciding to put an end to the brewing storm.

”You should all get along. Besides, I’m in good health. I can handle it.”

”One-three-five for carriers, two-four-six for battleships, Sundays off. Sounds fair, right?”

”…”

Jeanne Alter’s golden eyes scanned Setsuna and the two shipgirls for a moment before she said, ”Master, I’d suggest pacing yourself. If you end up with a bunch of little shipgirls running around, don’t expect me to help you raise them.”

”?!”

The entire room froze at her words.

”L-l-l-little shipgirls?! Is that even possible?”

”With the Commander?!” Taihou’s eyes sparkled with anticipation.

Richelieu’s expression turned complicated, and she seemed genuinely lost in thought.

”…”

Setsuna hesitated for a moment, then opened his species compendium. It didn’t seem to have any information on whether different species could have offspring together.

”Hey, system,” he called.

”Can humans and shipgirls have little shipgirls? Or humans and dragon girls have little dragon girls?”

Beep—

The system seemed to crash for a few minutes before replying in a muffled tone:

[In principle, offspring cannot be produced through conventional means between different species.]

”…”

Setsuna glanced between the shipgirls, heroic spirits, and dragon girls, feeling both a little disappointed and slightly relieved.

After that eventful morning, life returned to its usual rhythm for Setsuna.

He alternated between spending time with carriers and battleships, overseeing Gudako’s magic studies, and managing the growing responsibilities of the port and fleet.

Between flying battleships, commanding carriers, and mentoring Ritsuka Fujimaru on piloting a Gundam, Setsuna’s days were anything but mundane.

Ritsuka, also known as Gudako, had initially seemed unreliable, but her intelligence shone through as she mastered aerial maneuvers within a month.

”Boss, I want a more advanced mecha,” Gudako said one day, hopping out of the Zaku cockpit with a glint in her eye.

She had started by calling Setsuna ”Commander,” but eventually switched to ”Boss,” feeling it suited their dynamic better than ”Master.”

”How’s your magic training coming along?” Setsuna asked, noting her ever-present Chaldea uniform—a white jacket paired with a black skirt and stockings.

After spending so much time around Taihou, Richelieu, and Lucoa, he couldn’t help but find Gudako a bit… modest by comparison.

”That dragon lady knows a lot! She picks up Chaldea magic after just a glance. Even the Third Magic is just ’slightly troublesome’ to her…” Gudako scratched her head.

”I’ve learned the basics and even a few simple spells from their world.”

”Good. Let’s pick out a new mecha for you.”

Setsuna figured Lucoa’s guidance would keep Gudako focused on learning proper magic, so he decided to indulge her request.

...

They soon arrived at Akashi’s workshop, where the maintenance engineer was overseeing a group of Bulins.

In the workshop, several Gundams were lined up in pristine condition.

”Excluding my Strike Freedom, the most powerful models here are the Unicorn and Barbatos. Take your pick,” Setsuna said, gesturing toward the lineup.

The Unicorn Gundam, sleek and elegant in its pure white armor, held a shield and a high-energy beam rifle, exuding a refined aura.

In contrast, the Barbatos Gundam, with its blue, white, and yellow color scheme, looked rugged and imposing. It held a ten-meter-long hammer spear, clearly designed for close combat.

”That one!” Gudako declared, pointing at Barbatos.

”Oh, so you’re a melee type?” Setsuna raised an eyebrow, opening the cockpit door.

”Come with me,” Gudako said, motioning for Setsuna to join her in the cockpit.

”?”

”I’ve never piloted something this advanced before. What if I accidentally fall out of the sky and die? How would you explain that to Dr. Roman?”

Gudako gave him a mischievous smile, bordering on playful pleading.

”Teach me—please?”

”…”

Setsuna sighed at her antics but climbed into the cockpit.

Barbatos, though designed for a single pilot, had a slightly larger cockpit than Strike Freedom. Gudako’s petite frame left just enough room for both of them.

”Oh, wow, wow, wow—this thing’s leagues ahead of that trashy Zaku you gave me earlier!” Gudako exclaimed, twisting and fidgeting in excitement. She pulled levers, adjusted the balance wings, and fiddled with the controls like a kid with a new toy.

”Run diagnostics on the systems, then fire up the power unit,” Setsuna instructed.

”Let’s see how much you’ve learned.”

Unlike Setsuna, who could summon and operate mechs as easily as deploying a Susanoo, Gudako had to rely on pure skill and practice.

She was a genuine Gundam pilot, mastering each maneuver and technique from scratch.

Whirrrr—

As the workshop’s ceiling opened, Barbatos activated its propulsion system, sending out a burst of plasma jets.

The intense thrust pushed them back in their seats as the Gundam rocketed skyward at subsonic speed.

”Ohhhhh—this is incredible!” Gudako yelled, exhilarated.

As Barbatos soared through the skies, Gudako’s excitement only grew.

She piloted the Gundam with confidence, weaving through clouds, skimming low over the ocean to create sprays of water, and executing sharp, high-speed maneuvers.

Down below, a group of Bulins clapped their hands in awe, cheering as the Gundam’s shadow darted across the landscape.

Her mastery over Barbatos made it hard to believe that just weeks ago, she had been struggling through the basics of Chaldean magic.

”…”

Watching from his position in the cockpit, Setsuna couldn’t help but feel impressed. Gudako’s skill with the Gundam was beginning to rival protagonists like Kira Yamato or Mikazuki Augus.

The only problem? She had veered wildly off course from learning proper magic.

”Hmm?”

While teaching Gudako how to handle Barbatos’ complex weapon systems, Setsuna suddenly realized something—Gudako had shifted positions without noticing and was now sitting squarely on his lap.

The cockpit was small, and her enthusiastic movements to operate the Gundam’s controls made the situation… complicated.

The warmth of her body pressed against him left Setsuna stiff—not just physically, but mentally.

And Gudako, oblivious as ever, continued to throw herself into the controls with exaggerated motions.

”Can you… tone it down a little?” Setsuna began, his voice tight with discomfort.

”Boss.” Gudako’s voice cut through the moment, and her sudden seriousness made him pause.

”I’ve learned something important from my brief time at Chaldea: the more you study magic, the more you realize that a Master’s potential has its limits.”

”…?”

”What are you getting at?” Setsuna asked, a sinking feeling in his chest. The words felt eerily familiar.

”I’m done being a Master!” Gudako declared dramatically.

”Commander is a way cooler title!!!”

Before Setsuna could react, Gudako raised her hand, conjuring a flurry of glowing magic circles.

—Physical Structure Reinforcement—

—Speed Amplification—

—Reaction Enhancement—

—Mental Fortitude Augmentation—

Whoosh—

Barbatos’ frame shimmered with a kaleidoscope of magical enhancements.

The Gundam’s physical strength and speed skyrocketed to unprecedented levels, its exterior glowing with a surreal brilliance.

BOOM—

The sudden eruption of a sonic boom announced Barbatos’ acceleration. The Gundam rocketed forward at triple its cruising speed, the horizon disappearing behind it in seconds.

”Ohhh—” Gudako cheered, steering the Gundam toward the upper atmosphere.

The immense velocity sent them careening side to side in the cockpit, nearly throwing them out of their seats. Only the magical reinforcement kept the Gundam from tearing itself apart under the strain.

”This is my new magic! Cool, right?!” Gudako turned to Setsuna with a grin, clearly fishing for praise.

Whack!

Setsuna flicked her forehead hard enough to make her yelp.

”So all that training with Lucoa led you to develop… Gundam-enchanting magic?!”

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